Conventional fabric folding machines adopted for use with circular knitting machines now on the market can be divided into half-width fabric folding machines and full-width fabric folding machines according to the fabric folding width. On a full-width fabric folding machine, the fabric folding machine is located in a circular knitting machine which continuously knits and produce fabric, the fabric folding machine concurrently folds the lowering fabric at a maximum width. On the other hand a half-width fabric folding machine folds the fabric at a width one half of the full-width fabric folding machine.
The half-width fabric folding machine has drawbacks in use. After the fabric is knitted by the circular knitting machine, it has to be treated in a dyeing process. A dyeing tank usually can hold a fixed amount of fabric in the dyeing process. The fabric has a head and a tail that are connected to reach the fixed amount of quantity before being loaded into the dyeing tank to do dyeing process. Due to the half-width fabric folding machine provides a batch of fabric only one half of the full-width fabric folding machine, after the dyeing process is finished the head and tail portions of the fabric that are not evenly dyed have to be cut off. This results in a greater amount of waste. Reducing the waste can reduce the material cost. Hence the main stream of the market of the fabric folding machine for circular knitting machines is the full-width fabric folding machine that can fold the fabric at the maximum full-width.
However, the conventional full-width fabric folding machine still has its share of problems. Refer to FIGS. 1A and 1B for the conventional fabric folding machine in operating conditions. As shown in FIG. 1A, when a circular knitting machine continuously knits a fabric 7, if the fabric 7 does not sag naturally below a fabric spreading roller set 2 and above a fabric folding bar set 5, the fabric below the fabric folding bar set 5 increases gradually at the same amount knitted continuously by the circular knitting machine. If the driving wheel 3 rotates continuously clockwise to drive a chain 4 to move the fabric folding bar set 5 horizontally rightwards, the fabric folding bar set 5 flatly spreads the increased fabric 7 beneath thereof on a fabric loading board 6 same as the mount knitted by the circular knitting machine. If the driving wheel 3 continuously rotates clockwise to drive the conveying chain 4 to move the fabric folding bar set 5 horizontally rightwards, the fabric folding bar set 5 can flatly spread the increased fabric beneath thereof same as that knitted continuously by the circular knitting machine on the fabric loading board 6. However, after the fabric folding bar set 5 has moved horizontally rightwards, the fabric 7 below the fabric spreading roller set 2 and above the fabric folding bar set 5 has two problematic conditions, first the fabric folding bar set 5 has to be incorporated with an automatic faster fabric conveying means (such as a programmable controlled motor to generate faster rotation) to deliver the fabric faster below the fabric folding bar set 5. But such an approach often creates another problem as shown in FIG. 1B in which the fabric 7 laid on the fabric spreading board is creased. On the other hand, if the fabric folding bar set 5 does not automatically convey the fabric faster, the fabric originally hung below the fabric spreading roller set 2 and above the fabric folding bar set 5 sags as shown in FIG. 1B. When the fabric folding bar set 5 moves horizontally the sagged fabric hinders its movement and could cause machine jam. To overcome the problems shown in FIG. 1B, a preferable approach is to move the fabric folding bar set 5 rapidly beneath the fabric spreading roller set 2 where the fabric 7 is delivered before it is knitted by the circular knitting machine, and the fabric 7 which is originally located below the fabric spreading roller set 2 and above the fabric folding bar set 5 also has to be conveyed at the same time beneath the fabric folding bar set 5 to be flatly spread on the fabric loading board 6. Then machine jam can be prevented when the fabric folding bar set 5 moves horizontally. While the aforesaid approach seems advisable in principle, in practice no physical technique is yet available to move the fabric folding bar set 5 rapidly beneath the fabric 7 delivered by the fabric spreading roller set 2 before the circular knitting machine actually knits the fabric 7.
In short, the conventional half-width and full-width fabric folding machines still have problems in practice, notably:
1. The half-width fabric folding machine provides fabric only one half of the full-width fabric folding machine. After the dyeing process the head and tail ends of the fabric 7 have to be cut off that creates a lot of scraps. Waste of manpower and material occurs.
2. The conventional full-width fabric folding machine cannot flatly spread the fabric without generating creases during the return movement of fabric folding. The creases are difficult to flatten after being compressed by the weight of the fabric laid on the upper side.
3. During the return movement of fabric folding of the conventional full-width fabric folding machine the fabric above the fabric folding bar set 5 easily sags before lowering and folding due to inadequate tension of the transverse fabric 7. This hinders the horizontal return path of the fabric folding bar set 5 and could cause machine jam.
All the problems mentioned above related to the half-width and full-width fabric folding machines are still existed in the industry pending to be resolved.